Apparatus for casting workpieces having radially extending wings

ABSTRACT

Apparatus for the casting of workpieces, such as pump rotors or stackable elements, made of a refractory material and having wings extending from a central boss. This apparatus comprises internally cooled metallic wedges radially arranged around a central void and comprised between a bottom plate and a centrally perforated cover, which are mobile between two extreme positions corresponding to the casting position and to the position of extraction of the cast workpiece. The wedges can be radially moved or swung around horizontal axles.

United States Patent 1191 Recasens 1*Apr. 30, 1974 APPARATUS FOR CASTING WORKPIECES HAVING RADIALLY EXTENDING WINGS [75] Inventor:

[73] Assignee: LElectro-Refractaire, Paris, France Joseph Recasens, Sorgues, France Notice: The portion of the term of this patent subsequent to Oct. 10, 1989, has been disclaimed.

22 Filed: Aug. 29, 1972 [21] Appl. No.: 284,597

Related US. Application Data [63] Continuation-impart of Ser. No. 146,962, May 26,

[30] Foreign Application Priority Data May 26, 1970 France 70.19102 [52] US. Cl. 249/81, 425/468 [51] Int. Cl [58] Field of Search 249/108, 110, 81, 120,

[56] References Cited UNITED STATES PATENTS 337,764 3/1886 Gulliver..... 249/161 X 1,514,859 11/1924 Menz 249/108 X 3,598,175 8/1971 Olsson et al. 249/110 X 3,697,037 10/1972 Rccasens 249/81 FOREIGN PATENTS OR APPLICATIONS 681,847 2/1930 France 425/330 797,063 2/1936 France 249/172 Primary ExaminerRobert D. Baldwin Attorney, Agent, or Firm-Watson, Cole, Grindle &

Watson [5 7] ABSTRACT Apparatus for the casting of workpieces, such as pump rotors or stackable elements, made of a refractory material and having wings extending from a central boss. This apparatus comprises internally cooled metallic wedges radially arranged around a central void and comprised between a bottom plate and a centrally perforated cover, which are mobile between two extreme positions corresponding to the casting position and to the position of extraction of the cast workpiece. The wedges can be radially moved or swung around horizontal axles.

5 Claims, 6 Drawing Figures PATENTEDAPR so 191 3.807583 SHEET 1 [IF 2 PATENTEDmsmsm sum 2 UF 2 FIG. :5

APPARATUS FOR CASTING WORKPIECES HAVING RADIALLY EXTENDING WINGS This is a Continuation-in-Part of my co-pending application Ser. No. 146,962 filed May 26, l97l.

The present invention relates to an apparatus for the casting of molten refractory material into workpieces comprising a central boss and wings extending radially therefrom, such as pump rotors for dense liquids or stackable members for the construction of thermal regenerators or recuperators, such as those disclosed in the Recasens et al. US. Pat. application Ser. No. 264,954 filed on June 2l, 1972 for Improvements in refractory members for use in thermal regeneratorsor recuperators. These workpieces have more or less, in cross-section, the form of a star and will be conveniently termed hereinafter star-shaped workpieces.

Hitherto, intricated workpieces made of fused refractory material were produced by casting molten refractory material in sand or graphite molds. Such molds have the drawback to have a limited life in service so that the cost of the manufacture of said workpieces is 7 increased by thecost of the used mold. Also, the rate of manufacture of said workpieces is limited by the rate of production of the molds.

Also, cooled metallic molds are known, but their use has been limited to the production of simple shapes such as blocks or slabs.

Thus, there is a need for a an apparatus permitting the casting of star-shaped workpieces and having a long life in-service.

Consequently, it is an object of the invention to provide such an apparatus.

A further object of the invention is to provide an apparatus for casting refractory star-shaped workpieces and permitting to vary easily some characteristics of the workpieces such as the diameter of the boss and the thickness of the wings, at will.

According to the invention, this apparatus comprises a bottom plate, metallic wedges cooled internally by a circulation of'cooling fluid, said wedges being mutually spaced and arranged circularly and radially from a common central void or free space and resting on said bottom plate; vertical elements confining the volumes existing between the wedges provided at the periphery of these latters; and top confining means of said volconnection between the wings and the boss, the edges of the wedges adjacent to the common central void are rounded.

The bottom plate may be made of any suitable refractory material (e.g., graphite) or of metal, subject to the provision of internal cooling in the latter case. The top confining means may consist, for example, of a removable cover, comprising two separable parts made of an appropriate material, e.g., metal or graphite.

The feeding of the present apparatus with molten refractory material may be effected through the intermediary ofa feeding head or funnel resting on the top confining means and'centered on the central aperture. By choosing a central aperture of appropriate diameter, it is possible to control the rate of feeding of the apparatus, as it is obvious, and to ensure in every case a slow supply of molten material and correct filling of the volumes between the wedges.

Generally, the radial wings will be substantially flat, but it would be possible to impart them a shape deriving from the flat or plate shape by using artifices such as those disclosed in the aforementioned US. Pat. No. 3,697,047, the teachings thereof being incorporated therein by reference.

The present apparatus is particularly adapted for the production of pump rotors for dense liquids or stackable members for the construction of thermal regenerators or recuperators, i.e., for workpieces submitted to an important abrasion by fluids, because, by virtue of the cooling of the wedges, the obtained workpieces have a hardened fine texture which impart them particularly good anti-abrasion properties.

The following description, made with reference to the accompanying drawings, will fully explain how the invention can be performed.

FIG. 1 is a perspective view of an embodiment of the apparatus of the invention, the top confining means being omitted for the sake clarity;

FIG. 2 is a view in section along the line lI-ll of FIG. 1 0t this embodiment, the top confining means and a feeding head being in operative position, after a casting umes resting on said wedges and delimiting a central aperture; said wedges being mobile between two ex-.

treme-positions (corresponding respectively to the- According to a particular embodiment of the invention, the wedges are radially mobile between the-said extreme positions, and adjustable stop members are provided for controling the diameter of the common central void and, consequently, the thickness of the wings. The radial motion of said wedges can be e f' fected, for instance, by jacks or any other appropriate actuating means.

According to an other-embodiment, the wedges are swingable between the said extreme positions.

The number of wedges should be at least three. Said wedges may be made, for example, of copper or steel. Advantageously, in order to have the strongest possible operation;

FIG. 3 is a perspective view of two adjacent wedges of the apparatus of'FIGS. 1 and 2;

. FIG. 4 is a perspective view showing the cast workpiece obtained with the apparatus of FIGS. 1-3;

FIG. 5 is a schematic top view of an other embodiment of the apparatus of the invention, the top means being omitted; and

FIG. 6 is a view in section along the line Vl-Vl of FIG. 5, the top confining means and the feeding head being in operative position after a casting operation.

FIGS. 1 to 3 illustrate an apparatus according to the invention. This apparatus comprises a plate-shaped bottom 1 made of a' refractory material, for example graphite, upon which rest 12 steel wedges 5, mutually spaced, arranged'circularly and radially around a central void or free space 4, having lateral walls 6 (200 200 mm in size) and a summit angle at equal to 30, cooled internally by water entering through flexible pipes 7 and leaving by flexible pipes 8 respectively connected to circular water feed and discharge manifolds 9 and 10. On the external vertical face of one wedge in two, welded plates 11 are provided which come to' rest'upon the external vertical faces of the adjacent wedges which have no welded plates, so as to close the spaces existing between the wedges. Asso- 3 ciated with each wedge 5 is a hydraulic jack 12, the rod 13 of which is fixed to said wedge. The manifolds 9, I and the jacks 12 are fixed to crowns 14 forming a frame arranged around and at a distance from the wedges 5. Associated with each rod 13 is a butt 2 cooperating with an adjustable stop member 3, such as a screwable element, for the purpose of controling the length of the course of each jack toward the central void 4 and, thus, the diameter of this void and the thickness of the wings 'of the workpieces. On the wedges 5 rest a removable cover in two parts, 50 mm thick, formed ofa refractory material such as graphite, and provided with a central aperture 16. Above the aperture of the cover is positioned a removable feeding head 17, made of two parts, formed of a refractory material such as graphite.

The bottom, the wedges, the welded plates and the cover delimit volumes 18 (12 in all) of flat parallelepipedic general shape communicating through the central aperture with the feeding head.

The operation of this apparatus is a follows The cover 15 and the feeding head 17 being in position above the wedges, the apparatus being brought into its casting position, i.e., with the butts 2 engaging the stop members 3, by means of the jacks l2, and the water circulations being established, molten refractory material is poured into the feeding head acting as a funnel, then enters the central void 4 and the volumes 18 and comes to fill them. The material which fills the volumes l8 and the central void 4 is in contact with the cooled wedges and solidifies rapidly. After solidification, the cover and the feeding head, which are both removable in two parts, are removed and the jacks 12 are operated so as to bring the apparatus into its open position, i.e., with the wedges 5 away from their casting position. The solidified workpiece, having the form shown on the FIG. 4, is then extracted.

The thickness of the wings can be adjusted with the apparatus specifically described between some millimeters and 20 mm by adjusting, prior to the casting, the position of the stop members 3. These stop members fix, in fact, the limit of closure of the apparatus and, consequently, the spacing of the wedges in the casting or closed position of the apparatus.

When the extraction of the workpiece has been performed, it is subjected to annealing operation. The annealing conditions for the extracted workpiece depends upon its composition and particularly upon the thickness of the wings.

By way of example, workpieces comprising wings having thicknesses of 10 and 18 mm, respectively, have been prepared from a molten refractory compound having the following composition by weight ZrO 32 percent; SiO l6 percent; A1 0 51 percent; Na O 1.1 percent; various impurities 0.9 percent.

The annealing methods disclosed by Fulcher in U.S. Pat. No. 1,615,750 or French Pat. No. 619,489 are gene-rally satisfactory for annealing the produced workpieces. v v

However, for workpieces having wings 10 mm thick,

natural coolingin kieselguhr produces split or even broken workpieces. In a thermically insulated box, results are better andit is possible to take out the workpieces about 24 hours after they have been put in the box. Good workpieces are obtained by using a thermically insulated box preheated to l,200C, which is then allowed to cool naturally within about 24 hours, or by using a kilm at l200C with a scheduled temperature fall. It therefore appears that workpiece with thin wings 10 mm or less) have too low a thermal capacity to permit natural annealing, and that a rapid cooling on contact with a cold annealing medium (kieselguhr or silica, for instance) is harmful to them.

For workpiece with Wings 18 mm thick, the annealing conditions are not so severe and satisfactory results are obtained even with a natural cooling in kieselguhr or silica. This may be explained by the fact that these workpieces have a higher thermal capacity than the workpieces with 10 mm thick wings, so that they can supply more calories for heating the annealing medium.

FIGS. 5 and 6 illustrate an other embodiment of the apparatus of the invention. In these figures parts corresponding'to the parts of FIGS. l-3 are designated by the same reference numbers. This embodiment comprises only four wedges 5 and is useful, for instance, for making stackable members such as those disclosed in the previously mentioned pending U.S. application to Recasens et al. The general construction of this embodiment is analogous to that of the embodiment of FIGS. 1-3 (the water feeding and discharge element have been omitted for the sake of clarity). The only differences lie in the actuation of the wedges from the closed (casting) position to the open position of the apparatus and vice-versa. Instead to be radially actuated forwards and backwards, as in the previously disclosed embodiment, the wedges 5 can be swung up and down from the closed position (shown in FIG. 6) to an open position (not shown) and vice-versa, somewhat in the manner of flower petals. To this purpose, each wedge is pivotably mounted around an horizontal axle 30 at its bottom rear middle portion, and is fixed to one end of a lever 31 the other end of which is articulated at 32 to a rod-like member 33 which is itself articulated at 34 to a member 35 integral with the free end of the rod 36 ofa hydraulic jack (not shown). As shown, the vertical edges of the wedges which are adjacent to the central void are rounded in order to improve the strength of the connections between the wings and the central boss of the workpiece.

The operation of this embodiment is a follows After casting and solidification of the cast molten material, the feed head and the cover are first removed, then.the jack is actuated so as to lower the rod 36 thereof. This lowering action of the rod 36 is transformed into an upwardly swinging movement of each of the wedges by the rod 33 and the lever 31, as it is ob-,

vious. This movement of the wedges release the cast solid workpiece and this latter is then extracted. After extraction of the workpiece, the rod 36 is upwardly extended so as to bring back the wedges in the closed position. After positioning the cover and the feed head, a

further casting operation can be effected.

The embodiment of FIGS. 5 and 6 is simpler to construct than the embodiment of FIGS. 1-3. However, it does not permit to vary so easily the thickness of the wings of the workpieces'Such a variation could be, however, made by providing several spaced axles 30 or by providing means for varying the position of the axle I claim:

1. Apparatus for the casting of workpieces made of refractory material and having wings extending radially from a central boss, said apparatus comprising a bottom plate, metallic wedges cooled internally by a circulation of cooling fluid, said wedges being mutually spaced and arranged circularly and radially from a common central void or free space and resting on said bottom plate; vertical elements confining the volumes existing between the wedges provided at the periphery of these latters; and top confining means of said volumes resting on said wedges and delimiting a central aperture; said wedges being mobile between two extreme positions (corresponding respectively to the casting position and to the position for extraction of the cast solidified workpiece from the apparatus), toward and away from the common central void and the central aperture communicating with the volumes between the wedges.

2. Apparatus according to claim 1, wherein the actuated lever. 

1. Apparatus for the casting of workpieces made of refractory material and having wings extending radially from a central boss, said apparatus comprising a bottom plate, metallic wedges cooled internally by a circulation of cooling fluid, said wedges being mutually spaced and arranged circularly and radially from a common central void or free space and resting on said bottom plate; vertical elements confining the volumes existing between the wedges provided at the periphery of these latters; and top confining means of said volumes resting on said wedges and delimiting a central aperture; said wedges being mobile between two extreme positions (corresponding respectively to the casting position and to the position for extraction of the cast solidified workpiece from the apparatus), toward and away from the common central void and the central aperture communicating with the volumes between the wedges.
 2. Apparatus according to claim 1, wherein the wedges are radially mobile between the said extreme positions, and adjustable stop members are provided for controling the diameter of the common central void and, consequently, the thickness of the wings.
 3. Apparatus according to claim 1, wherein the radial motion of the wedges Is effected by jacks.
 4. Apparatus according to claim 1, wherein the wedges are swingable between the said extreme position.
 5. Apparatus according to claim 4, wherein each wedge is pivotally mounted around an horizontal axle and is swingable around said axis by means of a jack-actuated lever. 